Multiple propeller fan



Jufly 17,1923. 1,462,151

J. M. SEYMOUR MULT I PLE PROPELLER FA N Filed May 18, 1922 IN V EN TOR.

JMJHASQmMK BY ATTORNEYS.

Patented July '17, 1923.

unrao STATES JAMES M. SEYMOUR, OF NEWARK, NEW JERSEY.

MULTIPLE PROPELLER FAN.

Application filed May 18,

To all whom it may concern Be it known that 1, JAMES M. SEYMOUR, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Multiple Propeller Fans; and I do hereby declare the following to be a full, clear, and exact de scription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, and to characters of reference marked thereon, which form a part of this specification.

This invention has reference, generally, to improvements in fluid circulating fans of the propeller type; and the invention relates, more particularly, to a multiple propeller type air circulating fan.

It is well known to all engineers that the propeller type of fan is only efficient at very low pressures because of the slow move ment of the fan-blades near the center or axis of rotation. The efliciency of such type of fan is reatly decreased where the same is made 0 comparatively large diameter, since, although the peripheral speed of the fan-blades may be sufiicient to propel air against a given pressure, the hub or axis speed is so slow that there is a return volume of air through the center of the fan. This area of return draft extends from the center of the fan toward its periphery, and is variable as the back pressure varies or the speed of the fan varies. To overcome these difficulties I have heretofore developed and patented propeller type fans having closed centers in one instance, and in another instance l have used in combination with the center portion of the propeller fan a multivane or centrifugal type fan, which delivered air at right angles to the axis and ahead of the outer portions of the. propeller fan-blades, thus augmenting the flow of air propelled by'the latter. These fans while an improvement over the simple propeller type are not entirely satisfactory, I have, therefore, developed a multiple propeller type fan which is the subject of this invention, andwhich is adapted to overcome the objections or disadvantages which have been referred to above.

It is the principal object of this invention to provide a propeller fan consisting of a plurality of relatively concentric fan-blade 1922. Serial No. 561,816.

sets independently rotatable about a common axis, the inner set of blades being driven at a speed approximating the peripheral speed of the outer blades, or at aends of the inner fan-blade set, so that the air streams move efiiciently in a forward direction from the delivery face of the fan. The novel construction of fan thus provided renders possible the movement of air throughout substantially the entire crosssectional area of a pipe or conduit served by the fan, since a large dead center area in the fan is eliminated.

Other objects of this invention, not at this time more particularly enumerated, will be clearly understood from the following detaileddescription of the same.

With the various objects of the invention in view, the same consists, primarily, in the novel construction of propeller fan hereinafter set forth; and, the invention consists, furthermore, in the various arrangements and combinations of parts, as well as in the details of the construction thereof, all of which will be hereinafter more fully described inthe following specification, and defined in the claims appended thereto.

The invention is clearly illustrated in the accompanying drawings, in which Figure 1 is a face view of a multiple propeller type fan, made according to and embodying the principles of this invention; and Figure 2 is a vertical longitudinal cross section through the same, taken on line 2-2 in said Figure 1.

Similar characters of reference are employed in the said views, to indicate corresponding parts.

Referring now to said drawings, the reference character 1 indicates the front frame plate and 2 the rear frame plate of a supporting frame-work or housing in which the novel multiple fan is mounted. Each frame plate 1 and 2 has a central opening approximating the diameter of the fan devices, and

centrally disposed relative to said openings are bearings 3 supported by spider arms 4 radiating therefrom to the margins of said openings. Said frame plates 1 and 2 are spaced longitudinally apart a suitable distance, and are secured to ether by means 9f tie-bolts 5. Secured to t e rear side of'said frame-plate 1 is an annular housing flange 6 within which the fan elements rotate.

Journaled in and between said bearings 3 is a main shaft 7. Fixed on said main shaft 7, toward its forward end, is a hub 8 from which radiate a series of spokes or arms 9, upon the outer ends of which is fixed an annular casing or shield 10, which is thus concentrically disposed intermediate said mam shaft 7 and said housing flange 6, and spaced inwardly relative to the latter. Secured to the outer side of said casing or shield 10 are aplurality of radiating fan-blades 11 which are disposed intermediate the casing or shield 10 and the housing flange 6. The said hub 8, spokes or arms 9, shield or casing 10 and fan-blades 11 together constitute a main propeller type fan element of comparatively large diameter provided with an open center portion 12 enclosed by the casing or shield Rotatably mounted on said shaft 7, intermediate the hub 8 of said main fan element and the center bearing of said rear frame plate 2, is a sleeve 13. Secured upon the forward end of said sleeve 13 are a plurality of radiating fan-blades 14, which are arranged within the center opening of said main fan element so that their outer ends are encircled by said annular casing or shield 10. The set of fan-blades 14 thus arranged constitute an auxiliary fan element operating within the open center of said main fan element. Said main fan element and said auxiliary fan element are independently rotatable, and to this end the main shaft 7 is provided, adjacent to its rear end, with a driving pulley 15 driven by abelt 16, or any other suitable transmission means may be provided for rotating said shaft 7 and the main fan element mounted thereon; and, in like manner, the sleeve 13 is provided, adjacent to its rear end, with a driving pulley 17 driven by a belt 18, or any other suitable transmission means may be provided for rotating said sleeve 13 and the auxiliary fan element mounted thereon.

It will be apparent that the separate :fan elements thus provided may be driven at relatively different speeds, so that the center or auxiliary fan element may be run at a speed approximating the peripheral speed attained by the main fan element. In such case the tendency to loss of propelling efficiency at the center of the main fan is overcome by the operation of the auxiliary or center fan, and consequently substantially the entire cross sectional area of air forward of the fan is propelled onward with a minimum of loss through back draft or dead center eddies; furthermore, the provision of the annular casing or shield mounted in connection with the main fan element, and

aceaaar surrounding the ends of the fan-blades of the center or auxiliary fan element, prevents the air from spilling away from the ends of the latter fan element into the path of movement of the air through the main fan element, thus further preventing the formation of counter eddy currents tending to interfere with the proper desired flow of air through and propulsion thereof by the main fan element. This shield may be made stationary instead of rotatable, if desired.

It will also be understood, that the relative speeds of the main fan and auxiliary fan may be varied according to given result desired to be attained; and, furthermore, that the respective pitches at which the blades of the respective fan elements are set may be relatively varied to effect an equalized propelling speed and compensation of movement of the air by the respective fans, so that a substantially equalized movement of the entire air mass propelled by the multiple fan as a Whole may be thus attained.

While I have illustrated the principles of my invention as embodied in a duplex fan arrangement, it will be understood that the multiple fan arrangement broadly includes the provision of additional sets of concentrically arranged and independently rotatable fan-blades if desired.

I am aware that some changes may be made in the various arrangements and combinations of the several devices and parts, as well as in the details of the construction of the same, without departing from the scope of this invention as set forth in the foregoing specification, and as defined in the appended claims. Hence, I do not limit my invention to the exact arrangements and combinations of the various devices and parts as described in said specification, nor do I confine myself to the exact details of the construction of said parts as illustrated in the accompanying drawings.

I claim 1. A multiple propeller fan, comprising a main fan element having an open center portion, an auxiliary fan element alined with the open center portion of said main fan element, said fan elements being arranged in concentric relation to rotate about a common axis, and means for independently rotating said respective fan elements.

2. A multiple propeller fan, comprising a main fan element having an open center portion, an auxiliary fan element alined with the open center portion of said main fan element, said fan elements being arranged in concentric relation to rotate about a common axis, an annular shield disposed intermediate the inner ends of the blades of said main fan element and the outer ends of the blades of said auxiliary fan element, and means for independently rotating said respective fan elements. a

3. 'A multiple propeller fan, comprising a frame work having center bearings, a main shaft journaled in said bearings, an outer set of radiating fan-blades, means for mounting said outer set of fan-blades on said shaft so as to provide an 0 en center space intermediate said shaft an the inner ends of said fan-blades, a sleeve rotatable on said shaft, an inner set of radiating fan-blades secured to said sleeve and alined with said open center space provided by said outer set of fan-blades, means for rotating said main shaft, and means for rotating said sleeve independently of said main shaft.

4. A multiple propeller fan, comprising a frame work having center bearings, a main shaft journaled in said bearings, an annu- 'lar shield member concentric to the axis of sleeve and disposed so as to be surrounded by said annular shield member, means for rotating said shaft to revolve said outer set of fan-blades, and means for rotating the sleeve to revolve said inner set of fan-blades independently of said outer set of fanblades.

5. A multiple propeller fan, comprising an inner fan element consisting of a plurality of radiating fan-blades, an outer fan element consisting of a plurality of radiating fanblades arranged in a concentric row about the outer ends of said fan-blades of the inner fan element, and means for independently rotating each fan element.

6. A multiple propeller fan, comprising an inner fan element consisting of a plurality of radiating fan-blades, an outer fan element consisting of a plurality of radiating fanblades arranged in a concentric row about the outer ends of said fan-blades of the inner fan element, an annular shield member intermediate the inner ends of the outer fan-blades and the outer endsof the inner fan-blades, and means for independently rotating each fan element.

7. A multi le propeller fan, comprising a plurality o concentrically disposed rows of radiating fan blades, means for independently rotating each row thereof, and a concentric annular shield member intermediate the rows of fan-blades.

In testimony, that I claim the invention set forth above I have hereunto set my hand this 15th day of May, 1922.

JAMES M. SEYMOUR.

Witnesses:

'Gnonen D. Rromnos,

EVA E. DESCH. 

